Symptom Simulation

SYMPTOM SIMULATION






HINT: The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. Then the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be simulated. No matter how experienced or skilled a technician may be, if he proceeds to troubleshoot without confirming the problem symptoms, he will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting.

a. Vibration method: When vibration seems to be the major cause.

HINT: Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is turned to the ON position).

1. Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs.

HINT: Shaking the relays too strongly may result in open relays.

2. Slightly shake the connector vertically and horizontally.
3. Slightly shake the wire harness vertically and horizontally.
The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.

b. Simulation method for DTC B1794: Turn the ignition switch from the LOCK to ON, hold for 10 seconds, and back to LOCK again 50 times in a row.

HINT: DTC B1794 is output if the occupant classification ECU receives the ignition switch LOCK-ON-LOCK signal 50 times in a row when a malfunction occurs in the power circuit for the occupant classification system.